Salt water on foam mattress

[bdh198]

Yep... the front hatch wasn’t closed properly when we sailed through a lumpy sea! By the time we realised it wasn’t properly shut, quite a few waves had broken over the bow and soaked the mattress.

I’ve dried the mattress out, but of course it gets damp again because of the salt crystals in the cover and the foam. I’m planning to wash the cover on a cold slow wash and hopefully that should get the salt out, but I’m not sure what is best to do with the foam. I’ve read some old threads where the solution seems to be plenty of fresh water to soak it, squeeze it out and soak again (and possibly again) followed by a warm room and dehumidifier for a few days.

Has anyone tried this, and does it work? I’m also aware that with winter approaching we’re not going to be able to leave it in the fresh air and warm sunshine. The alternative is to replace the foam, but we’d be looking at a replacement cost of £250-300, so if we can flush the salt out ourselves that would be the preferred option.

 

[lustyd]

It does work but it's a thankless job that takes forever. "squeezing out" 4-5" thick foam isn't really possible so you'll end up waiting for it to drain and probably do a less than thorough job. It'll be good enough for a season or two though so better than paying out

 

[Dipper]

If you do wash/rinse your foam, weigh it as it dries out and you can see when it is completely dry as it stops losing weight. I washed all the foam on my first boat and was surprised that it took several weeks to completely dry out. Mind you, that was 1960s foam. I think modern foam may be more closed cell and so absorb less water?

 

[[70521]]

Oh no! Can you store it overwinter somewhere with a dehumidifier, not onboard as they are the work of the devil.

 

[V1701]

It may be better to use cold water to wash/rinse the foam, that way any salt has less of a chance to dissolve and get deeper in than it already is. I learned this principle in the context of washing my motorbike after riding it in the winter when there's salt on the roads...

 

[Sea-Fever]

This is what mangles were invented for.

 

[JumbleDuck]

I have done this in the past by pressure washing the foam, to get the fresh water through effectively. Drying still takes ages. One of the quarter berth cushions in my Hunter 490 got waterlogged and it took around three months for it to dry, propped up in a dry and well ventilated shed.

 

[Channel Sailor]

I have fresh water swilled out several boat foam mattresses. The washing and squeezing out is OK to do to make a start on getting the water out. But the drying out is a problem. in warm sunny weather with a little breeze i did dry one out over a few days. But in the winter it was a right hassle to dry one out. I vaguely recall a De humidifier in the same room did not help much. It needed sunny warm weather with a little breeze, then still days of putting out in the sun, squeezing out from the bottom corners and turning over. If inside they do clutter up your house while they are drying

I like the mangle idea, if you could find one big enough. So maybe a very heavy garden roller might help.

 

[JumbleDuck]

I like the mangle idea, if you could find one big enough. So maybe a very heavy garden roller might help.

I imagine that the problem with that would be the same as trampling (which I have tried) which is that unless you provide somewhere for the water to go, it just gets soaked up again as the foam expands after being compressed. A mangle drives some water out but mostly it drives it to the final end of whatever-it-is. Some sort of heavy roller on a workbench, maybe?

 

[Spirit (of Glenans)]

Would it fit into one of those big coin-operated washing machines one finds at places like service stations etc?

 

[TernVI]

I've had to play this game.
I washed and rinsed the foam.
Then trampled it on a tiled patio.
Then put some old towels on the floor and trampled it again.
Went over it with a Wet'n'dry vacuum cleaner
Then put it in a warm room with a dehumidifier and a desk fan.

IT still took ages to get truly dry.
If you don't get it really clean, it may go mouldy before it dries.

 

[James_Calvert]

Obvious maybe but focus on the bit of the cushion that got wet in the first place...

 

[bdh198]

Thanks for the replies.

Having looked a bit closer I think the majority of the water soaked into the thick covering, and not so much actually soaked through to the foam. My initial plan is to wash the cover, and then to only wet the surface of the foam (perhaps with a wet sponge) being careful not to squeeze the water deeper into the foam. With a bit of luck the majority of salt crystals will be on, or very near, the surface of the foam.

If that doesn’t work, a power hose followed the suggested squeezing and drying techniques might be called for!

 

[KompetentKrew]

I think you're overthinking it. If you've got a dehumidifier and somewhere you can leave it with the wet mattress then just hose the damn thing down.

Sit it on the pontoon, hose it until water is running out of it and leave it for an hour before getting as much out as you can by squeezing it.

The dehumidifier will extract about 3 litres per day (mine is a "12 litre" model, but that is jungle conditions) and it won't take that long.